Method of making polished glass.



G. 0. DE BAY. METHOD OF MAKING POLISHED GLASS.

APPLICATION FILED MAY 26,1909.

Patented Oct. 11, 1910.

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INVENTOR Patented Oct. 11, 1910.

G. C. DE BAY.

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METHOD OF MAKING POLISHED GLASS.

APPLIOATIOH FILED my 28,1909.

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METHOD OF MAKING POLISHED GLASS.

APPLICATION FILED MAY 26,1909. 972, 1 65.

Patented Oct. 11, 1910.

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G. 0. DE BAY.

METHOD OF MAKING POLISHED GLASS.

' APPLICATION FILED KAY 26 1909. 972, 1 5, Patented 001. 11, 1910.

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INVENTOR WITN ESSES UNITED STATES PATENT OFFICE. I

GEORGE C. DE BAY, OF TARENTUM, PENNSYLVANIA, ASSIGNOR 0F ONE-HALF TOJOSEPH HEIDENKAMP, OF SPRINGDALE, PENNSYLVANIA.

METHOD OF MAKING POLISHED GLASS.

To all whom may concern:

Be it known that I, GEORGE C. DE BAY, a resident of Tarentum, in thecounty of Allegheny and State of Pennsylvania, have invented a new anduseful Improvement in Methods of Making Polished Glass, (Case 1,) ofwhich the following is a specification.

This invention relates to a method of forming polished glass in the formof sheets or plates and whereby glass having all of the qualities andcharacteristics of ground and polished plate glass can be produced veryquickly and cheaply.

The essential features of the invention consist in fire polishing thesurfaces of the glass under such conditions and in such manner as tomake the same perfectly smooth and without waves or irregularities, thehigh glaze of the fire finish giving the necessary polish and producingglass in all essential particulars the same as polished plate glass.

The present method of manufacturing polished, or what is known as plateglass, consists in forming the plate, preferably by rolling, andafterward subjecting the same to a grinding and polishing operation togive the desired smooth fiat surface. The grinding and polishing isaccomplished when the plate is cold and is a slow and rather expensiveprocess and is the principal factor in the high cost of polishing plateglass at present on the market.

It is well known that glass can be given a polished or highly glazedsurface by fire finishing the same, that is, by subjecting the same tosufficient heat to practically melt the surface of the glass, andvarious small articles of glass ware have heretofore been finished inthat way. This method has, however, as far as I am aware, not heretoforebeen adapted for finishing large sheets or plates of glass on bothsurfaces. This, I believe, is due to the fact that the necessary heatfor fire finishing is liable to leave a wavy or irregular effect on thesurface of the glass, and also to the difficulty of supporting the plateso as not to destroy the glaze or polish on the lower surface thereof.

My method has for its purpose to produce sheet or plate glass having allthe qualities Specification of Letters Patent.

Application filed May 26, 1909.

Patented Oct. 11, 1910.

Serial No. 498,553.

of cold polished plate glass and by fire finishing both surfacesthereof.

The invention comprises the process steps hereinafter described andclaimed.

In the accompanying drawings Figures 1 and 2 represent in plan view,partly in horizontal section, apparatus suitable for carrying out mymethod; Fig. 3 is an elevation showing the plate forming mechanism inside view; Fig. 4: shows part of the plate forming mechanism of Fig. 3and the re ceiving mechanism in vertical section; Fig. 5 is a viewsimilar to Fig. 4: showing the parts in a different position; Fig. 6 isa horizontal section through the leer, and Fig. 7 is a cross section ofthe leer taken through the heating chambers.

The apparatus shown includes a suitable furnace 1 for melting the glass,which may be either a tank or pot furnace or the like. The furnace shownis provided with a tank having a gate controlled slot 2 through whichthe molten glass escapes in the form of a thin wide stream formingpractically a sheet or plate. This passes down over the chute or guide 3which is supplied underneath with burners 4 for heating the same inorder to maintain the glass in molten condition. The thin wide stream ofglass passes in succession between three pairs of rolls 5, 6 and 7 whichact to form the sheet to uniform thickness, compact the same, and feedthe same forward. The first pair of rolls 5 are slightly fluted orcorrugated so as to impart a forward feed to the plate. The second pairof rolls 6 are also slightly corrugated for the same purpose while thethird pair of rolls 7 are smooth so as to press out the corrugationsimparted to the sheet by the first two pair of rolls. The first pair ofrolls 5, and preferably also the second pair 6, are water cooledinternally, such as by pipes 8, so as to cool the plate and give thesame sufficient rigidity for the subse' quent operations. The last pairof rolls is preferably heated, such as by the internal gas pipe 9, inorder to keep up the temperature of the surface of the glass sheet.These rolls are mounted in a suitable table and can be driven by anysuitable mechanism, the drawings showing for this purpose shafts andbevel gears driven from the longitudinal shaft 10. These rolls are onlyone form of sheet forming mechanism which may be employed.

The sheet or plate is subjected on its upper surface to the firefinishing process preferably immediately after leaving the formingrolls, at which time the sheet or plate is still at a high temperatureso that it is not likely to break and does not require a large amount ofheat to fire finish the same. My invention, however, is not limited inthis particular, as the fire finishing could be accomplished on analready cold sheet or plate, in which case, however, the sheet wouldfirst have to be heated up slowly to prevent breaking and a largeramount of heat would be necessary for fire finishing. The plate,however, must be fairly rigid by the time it is subjected to the firefinishing on its lower surface so as to practically support itself.

In the apparatus shown the top surface is first fire finished, afterwhich the bottom surface is similarly finished. Adjacent to the lastpair of rolls 7 is a suitable heater or furnace 11 located above thecourse of the sheet or plate and serving to fire finish the top surfacethereof. This furnace is provided with gas burners 12 and is lined withfire brick or the like and is maintained throughout at a very high heat,approximately at what may be called a glory hole heat. The flame is notintended to strike the surface of the glass, but the latter is melted bythe heat within the furnace. The heat finishing of the surfaces of thesheet may be accomplished by other devices than those shown. Thetemperature must be such as to quickly melt a thin skin on the surfaceof the plate so as to give the usual fire finish or polish thereto.This, however, is likely to leave slight waves or undulations or otherirregularities in the surface of the glass which would render it unfitas a substitute for polished plate glass without subsequent coldgrinding or polishing which I wish to avoid. To smooth out such waves,undulations or irregularities, the surface of the glass while stillpractically melted or plastic is subjected to a very light rubbingaction by means of a block 18 reciprocated by means of eccentric 1 1.This block exerts only a very light pressure on the surface of the glassand is formed of any substance which will not adhere to the glass andwill become heated so as not to chill the glass and which is perfectlysmooth so as to have no scratching or abrading effect on the glass.Various substances for this purpose may be used. A smooth steel surfacewill answer the purpose, but with very high heats there might be atendency of the glass to adhere thereto. A block of oak wood willanswer. I prefer a mixture of fine smooth carbon, such as charfiake,with a suitable binder therefor, such as plaster of paris, and such asdescribed and claimed in application of even date herewith, Serial No.498,555. Loose fine charcoal or other fine carbon may be fed between therubbing blocks and the glass, being rubbed, if desired, as shown in Fig.3. For this purpose the block is provided with a slot therethrough asshown. The rubbing action of this device smooths out the waves,

undulations or other irregularities, and gives.

a perfectly fiat surface to the glass, free from all scratches or scoresand without in any manner affecting the high polish or glaze given bythe fire finish, so that when the surface cools a perfectly smoothpolished effect is left. The lower surface of the sheet is similarlyfinished by means of a furnace 15 and a smoothing block 16 locatedunderneath the course of the glass sheet. The sheet by this time issufficiently rigid so that it supports itself over this device, which isnecessary for the reason that nothing but the smoothing device 16 mustcontact with the lower surface of the plate from the time that it issubjected to the action of the furnace 15 until it is cooled, asotherwise the glaze produced by the fire finishing would be destroyed.The smoothing block 16 in this case must be held up against the surfaceof the glass, such as by means of guide rods 17 moving in guides 18.

The devices described give to both surfaces of the plate a perfectlysmooth polished finish, and nothing further is necessary to complete theglass except to so handle it during annealing that this glazed smoothfinish is not disturbed or marred. According to my invention the platesare then transferred to suitable carriages or wagons for carrying thesame through the annealing oven or leer and the transfer to thecarriages is made in such way that there is no sliding movement betweenthe plate and carriage or other supporting device. The leer is shown at20 extending at right angles to the course of the plate, and is providedwith tracks 21 upon which run the carriages 22. These carriages are ofdouble construction having the bottom member running upon the tracks 21,said bottom member on its top surface being provided with ways or tracks2 at right angles to the tracks 21, upon which ways or tracks is mountedthe top or plate supporting portion 24 of the carriage. The top or platesupporting platform 24 is formed in sections, as shown, suit ably hingedtogether so that when said platform is moved off the bottom member ofthe carriage these sections fiex and extend downwardly on tracks 25 intoa pit 26.

. hen the edge of the plate reaches the carriage the platform Q-fl ispulled onto the bottom part of the carriage and at exactly the samespeed as the traveling plate, so that the plate is progressively fedonto these hinged sections and without liability of any relative slidingmovement between the plate and said sections. This prevents scratchingand otherwise marring the lower surface of the plate. The mechanism forpulling the hinged sections 24 onto the carriage will be driven from thesame source and at exactly the same peripheral speed as the plateforming mechanism, so as to insure non-slipping between the plate andits support. This is shown as accomplished by the rack bar 27 actuatedby gear 28 which is driven by suitable shafting and gears from the shaft10 of the plate forming mechanism.

The hinged sections of the platforms 2%. are preferably formed of thecomposition above described for forming the smoothing blocks, as it isfound that this substance has no affinity for hot glass and ispeculiarly well adapted to prevent dulling or clouding the lowerpolished surface of the glass plate in the annealing oven. The platewhile supported upon the carriages described is moved slowly through theannealing oven or leer 20 until properly annealed and emerges from thesaid annealing oven a plate of perfectly uniform thickness having bothsurfaces absolutely smooth and with a high glaze or polish thereon.

By the process described grinding and polishing is entirely omitted andthis slow and expensive step in the manufacture of plate glass avoided.The plates are of equal quality with those produced by'the presentexpensive methods, or if anything have a higher polish or gloss. Themanner of producing the same is very rapid so that the cost is very muchlower than according to present methods of making polished plate glass.Plates of any desired size can be manufactured according to this method.The plate forming apparatus will, of course, be as wide as the greatestwidth of plate to be formed and plates of any desired length can beformed by cutting off the flow of the stream of molten glass from thetank at the proper periods. The am'iealing oven must be of a widthcorresponding to the length of the longest plate to be annealed therein,since the plates are carried through the annealing oven with theirlengths crosswise of the annealing oven.

What I claim is:

1. The method of making polished glass consisting in forming a sheet orplate of uniform thickness by pressure between unyielding surfaces, andwhen rigid fire polishing one surface thereof,vand while still plasticsubjecting the same to a light rubbing action to smooth the same, andthen similarly fire polishing and smoothing the other surface of saidplate.

2. The method of making polished glass consisting in forming a sheet orplate of uniform thickness by pressure between unyielding surfaces, andwhen rigid but still hot fire finishing a surface thereof, and whilestill plastic subjecting said surface to the light rubbing action of abody of smooth substance non-adhesive to hot glass.

3. The method of making polished plate glass consisting in rollingmolten glass to form a sheet or plate of uniform thickness, and whenrigid fire polishing both surfaces thereof, and while said surfaces arestill plastic subjecting the same to a light rubbing action to smooththe same.

l. The method of making polished plate glass consisting in pouring athin fiat stream of glass of substantially the width of the desiredsheet and forming it into a sheet, rolling the same to uniformthickness, then when rigid but still hot fire polishing both surfacesthereof, and finally annealing said sheet or plate.

5. The method of making polished plate glass consisting in forming asheet or plate of uniform thickness by pressure between unyieldingsurfaces, then fire polishing the lower face thereof, then deliveringthe plate endwise onto a carrier having a flat supporting surface in amanner to prevent relative movement between plate and carrier, and whileon said carrier annealing said plate.

6. The method of making polished plate glass consisting in forming asheet or qolate of uniform thickness by pressure between unyieldingsurfaces, fire polishing the lower face thereof, then delivering theplate endwise onto the fiat surface of a traveling nonabradent supportand at the same rate of travel as the travel of said support, andcooling said plate while on said support.

7. The method of making polished plate glass consisting in forming asheet or plate of uniform thickness, then when the plate is rigid butstill hot and while in a horizontal position fire finishing both facesthereof, and annealing the same while supported throughout its entirearea by a substance non-adhesive to hot glass.

8. The method of making polished plate glass consisting in forming asheet or plate of uniform thickness by pressure between unyieldingsurfaces, then when the plate is rigid and while in a horizontalposition fire polishing both surfaces thereof, and finally annealingsaid plate while supported on the fiat surface of a body of smoothnon-abrading carbonaceous material.

9. The method of making polished glass consisting in rolling moltenglass to form a sheet or plate, then when rigid but still hot and whilein a horizontal position fire finishing both surfaces thereof, thendelivering In testimony whereof, I have hereunto set said plate to acarrier having a flat supportmy hand. ing face consisting of a substancenon-ad- GEORGE C DE B KY hesive to glass and in a manner to 'prevent 5relative movement between said plate and lVitnesses:

carrier, and While supported on said carrier F. W. WVINTER, annealingsaid plate. JOHN S. CORT.

